Food mixer



FOOD MIXER 3 Sheets-Sheet l Filed Dec.

Dec. 15, 1953 J. A. scHwARz 2,662,753

FOOD MIXER Filed Deo. 8, 1951 3 Sheets-Sheet 2 d f /f Dec. l5, 1953 J. A; scHwARz FOOD MIXER 5 Sheets-Sheet 5 Filed Deo.

llllll Mgg Patented Dec. 15, 1953 FOOD MIXER Joseph A. Schwarz, Chicago, Ill., assignor to Birtman Electric Company, a corporation of Illinois Application December 8, 1951, Serial No. 260,634

- 2 Claims.

This invention relates to a food mixer having a rotatable platform and relates particularly to such a food mixer including a platform and releasably attached bowl rotatable in one direction during the mixing operation and catch apparatus carried by the platform to prevent reverse rotation of the platform.

vIn certain types of food mixers the bowl adapted to `contain the material to be mixed is Vremovably locked on a rotatable platform by turning the bowl in one direction with respect to the platform. During the mixing operation the bowl and platform are rotated in this direction by the rotating beater blade or blades. Sometimes a brake mechanism is attached to the platform to govern the speed thereof.

At the end of the mixing operation it is necessary to disconnect the bowl from the platform so that the mixed contents may be removed from the bowl. This removal of the bowl requires reverse rotation of the bowl with respect to the platform. As the two are tightly joined to`- gether by this time because of the beater or beaters applying a force to the bowl that tends to wedge or lock the bowl tightly on the platform, it is Often diicult to unlatch'the bowl from the platform. In the present invention this problem is solved by providing a catch member carried by the platform and a stop means adjacent to the catch member. The catch-member is engageable with the stop means upon initial reverse rotation of the bowl and platform to prevent further reverse rotation of the platform and thus hold it While the bowl isI unlatched therefrom. This permits easy removal of the bowl from the platform by merely grasping the bowl and turning it slightly in a direction opposite to the normal direction of rotation.

The invention will be described as. related to the embodiments shown in the accompanying drawings, in which: K

Fig. 1 is a fragmentary side elevation of an electric food mixer and bowl combination em.- bodying this invention, with the bowl in place on themixer platform; Fig. 2 is a fragmentary enlarged side elevation of a portion of the mixer base showing the rotatable platform; Fig. 3 is a fragmentary plan view of the mixer section and platform of Fig. 2; Fig. 4 is a horizontal section through a portion of the mixer base, taken substantially along line 4 4 of Fig. 5; and Fig. 5 is a fragmentary vertical section through a portion of the mixer base and platform taken substantiallyv along line 5-5 of Fig. 3 and showing the bowl locked in place on the platform.-

In the embodiment shown in the accompanying drawings, the food mixer comprises a base l0, a substantially vertical standard II, a horizontal motor housing I2 rotatable about a pivot I la adjacent the top of the standard and a bowl I3 wardly into the bowl I3.

releasably attached in place on the base I0. The motor housing i2 includes the usual speed control knob I4 and a cap I5 covering a power shaft for an attachment. The motor housing I2 is rotatably attached to the standard I l at one end and adjacent the other end there is provided a beater includinga shaft I5 extending down- As is shown most clearly in Fig. 5, the bowl I3 is releasably attached to a rotatable platform I'I located on the base I0 and rotatable relative thereto. The bowl I3 which is described and claimed in my co-pending application Serial No. 247,317, filed September 19, 1951, is provided with a concave bottom portion I3a having a raised lower surface of inverted cup shape provided with a similarly shaped metal insert I8.' rThis metal insert which is shown, described and claimed in my above-mentioned copending application is provided with a plurality of openings I8a through which extend small portions I3b'of the material used to make the'base of the bowl I3. This material is preferably a synthetic plastic and the combination of the'plu'rality of holes |8a' and bowl portions I3b serve to distribute the stresses in the bottom part of the bowl and prevent breakage thereof.

The rotatable platform I'l is provided with a plurality of inclined cut-away surfaces Ila on its periphery adapted to be engaged by similarly inclined inwardly projecting portions I8b on the inner surface of the insert I8. The portions I'la and IBb on the platform and insert, respectively, provide a screw type connection between the bowl and the platform. Thus, in attaching the bowl to the platform the projections Ib on .the bowl are forced downwardly through the spaces I Ib to below the level of the inclined portion Ila and then the bowl turned in a clockwise direction to engage the portions I8b with the inclined surfaces Ila.

:The base I0 of vthe mixeris hollow and is provrvided with an upper wall Ilia having a circular opening defined by an upwardly extending annular vflange lob.' Ther platform I'I is located within this flange Ib and is attached Yby means of threescrews I9 located in three legs I'Ic toa disc20. This disc 20 also carries on its top surface an inverted rcup member 2l provided'at Aits center with a downwardly extending spindle 22'fof substantially circular cross section. This `spindleflZ is rotatable within an 'opening 23a that is within an upwardly extending part 23 of tating beater-.operating on the material within edge engaging a toothed spindle25. Thisspin- I? dle is thus rotated by rotationof the disc20 and is attached to a seconddiscZE which rotates at a considerably faster speed than does the first disc 20. This second disc 26 has rotatably attached thereto a pair of arcuate lever arms 21 e of gwhich one is-,shown |in- Fig. 5. Each fleverarm is. rotatably attached- -toy the disc 26 ationeend .of the arm by means of a spindle 28.and carries a brake shoeatthecther end. Theseabrake shoes Abeaxfzagainst the linner wall'of: the annu-lar'portion.` 24a forming'. a .part; of the V'closure' plate; 24.

-The .entire :.bralrey `mechanism :depends on centrifugal force urging theleverarms 2`|4 outwardly fagainst the .annular portion; 24a.

"In-.orderthat the platform 11 will rotate about 1.a fixed axis, the bottom closure plate-24 isproyvided-with a top vplatel-ZE'I-.spaced lfrom the substantially parallel .to thedisc 20. 'f'I'his top-,plate which Lis` fastened securely.` to the upper rim'524b `ofthe:.closure1-i2||, lisflprovidedV with an--annular t raised part24c that formsa .raceway for a series of .ball. bearingsi; located between: the disc-20 .fand platel'29.

"Withi :the construction'.` as described, the vbowl 'maybe .easily attached-to the .platform I1 by ,merelyrlowering-.the projections |8b on the vbottom off. the :bowl through' the-spaces on the Vplatform .and turning the z-bowlfrelative'to the zplatformmntil. these projections I8b slide :under the-inclined surfaces 11a. #When this has been Idone; the bowl and platform' are locked ltogether for rotation as a unit. AIThe force exerted bythe :beater oribeatersaon the'material'within the bowl y,causes rotation of the: bowland-`- platform, this vrotation -being braked :by-.the above described --.brake mechanism.

With vthis construction it has been founddiicult to removefthezbowl from thelplatform because reverserotationof the bowlalso normally :causesfreverse'rotation of1the1platforrn so that the iprojections.l |8b von the .bowl` remain'wedged zunder 'the :surfaces 1 lla. In order to overcome this, .theapresent invention*providesacatchmem- -ber13ly carried by the platform7 Hand rotatable therewithand a stopmeans: 32adjacentto.the

catch member and engageable therewith upon `initial reverse vrotation `of the .bowl .and platform to -prevent further reverse -rotation of the: platformso that the bowlemay be removed. In. the -embodiment shown,I and particularly'disclosed in iigs.;4and 5, .the catch :member-1 3| lis;,rotatably :mountedxaround ,a bolt :I9 `usedxtoiattach the l.platform-to;the'disc-'2 ,'This catch ymember ts within a cut-outportionr |1d ,in the 'depending inner skirt |'|e of the platform `as shownin Fig. y4. The-catchmember. is of generallycrescent sha-pe.; and vis f oscillatably mounted on the platform .about-,an axis adjacent ther-center of lthe crescent. The two ends .of the 'crescent :shaped catch `member project:v generally `away from .the

axis of-rotation of :thezzplatformi so 4as,` to .be en- .gageable with vthe stop means. v"Ihe stop means, es shownimost .clearlyin'liig V4,:includes a pluralityv of circularly. ,arranged stopY members Y 241 Aadjacent .the path. of frotationfofthe. catchomem- 4 ber 3|. In the embodiment shown each stop member 24j projects generally toward the axis of rotation of the platform and has av part 24g engageable with the end: 3|a of the catch member on initial reverse rotation of the bowl in the direction opposite the arrow in Fig. 4 to prevent :further reverse rotation of the platform and permit;removal of the bowl from the platform. As

shown in Fig. 4 the leading edge 24h of each stop-member 24) is'inclined at a relatively small angle with respect to the remainder of the stop means 32. `The following edge part 24g engaged by the end 3|a of the catch member is, in con- -trast to'this, relatively blunt so as to stop reverse rotation. With this construction, the leadingfedgeflhyengages a relatively blunt end"-3|b -of .the crescent shaped catchmember 31 :on nor- .mal rotation-of the bowl and platform to :move

,the relatively sharpopposite crescent end 3|a `into-position so thatit is always located in such Ka-.position ,thatait will engage a stop memberruf.

As can be seen, the stop members 241 -and the :catch-membervSI 3do not interfere with'normal rotation of the bowl and platform during `the vmixing operation, 4.but only serve to preventV ro- -tation of the platform when the yplatform is rotated in a reverse fmanner.

As is shown in the drawings, the catch member-32 is -formedin the cut-out central opening1 of the top plate 29 so that the stop.-members2lf are actuallyinivardlyprojecting teeth. This construction serves tonsave :space and Vweight Aand simplifies, the Alocatingof theca-tch member 3|.

i Havingadescribed -my invention as 'related' to i the embodiment shown sin the' accompanying drawings, it isV my intention' thatV the invention be not limited-.by any of Vthe* details of descrip- `tion unless otherwise specified but rather be con- I:strued .broadlywi-thin its spiritand scope as set .out in the accompanying claims.

I claim:

l. In a food `mixer, a rotatable platform, a mixer bowl, a friction interlock :for locking the .bowl on the platform against rotation-0f the bowl inits normal driven direction, a base having a circular opening into .whi ch 'the platform extends,

ythe -edge portion of the platform -dening the opening` being provided with a plurality of stop members around the platform forming a ratchet.

.and :a pawl carried -by `the .platform and engaging a tooth upon vinitial reverse rotation of the bowland platform to prevent further reverse rotationof the platform to aid lin separating the friction interlock.

.2. .The food mixerof claim l wherein the pawl is of generally crescent shape and oscillatably JOSYEPH'A. SCHWARZ.

ReferencesjCited in'the le of thispatent UNITED STATES- PATENTS Number vName Date 1,733,291 Aastrup Oct..;29, -l929 .2,013,765 Richardson .V ;,Sept. 10, 1935 v27,075,851 Johnson Apr. 6, 1937 2,5fl3,482 Williams Feb.v2'7. 1951 

